CVE-2026-99031: net: bridge: avoid recursive multicast port cleanup

Q: Which systems are exposed to this issue?

Systems using the Linux kernel bridge multicast code are relevant. The failure condition involves a large number of automatically added STAR_EXCL port groups associated with S,G multicast entries.

Q: What condition causes the stack exhaustion?

During cleanup, deletion of an automatically added STAR_EXCL port group can recurse back into S,G exclude-port cleanup. Each affected port can consume another kernel stack frame, and sufficiently many ports can reach the stack guard page.

Published Oct 23, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved:

net: bridge: avoid recursive multicast port cleanup

brmulticastsgdelexcludeports() removes automatically added STAREXCL port groups by calling brmulticastdelpg(). For S,G entries, that deletion calls back into brmulticastsgdelexcludeports(), so a large number of STAREXCL ports consumes one kernel stack frame per port and can hit the stack guard page.

Keep the complete port-group deletion path for cleanup, but suppress the S,G exclude-port cleanup while that helper is already walking the same entry. Normal deletion callers retain the existing behavior.

Affected Software

225 affected componentsFixes available

Linux Linux kernel

debian/linux*

debian/linux<6.12.113-1

6.12.113-1

debian/linux<7.2.11-1

7.2.11-1

linux/kernel>=5.10.0<5.10.273

5.10.273

linux/kernel>=5.11.0<5.15.224

5.15.224

linux/kernel>=5.16.0<6.1.191

6.1.191

linux/kernel>=6.2.0<6.6.160

6.6.160

linux/kernel>=6.7.0<6.12.113

6.12.113

linux/kernel>=6.13.0<6.18.57

6.18.57

linux/kernel>=6.19.0<7.2.11

7.2.11

debian/linux<=6.1.176-1, <=6.1.190-1, <=6.12.107-1

6.12.115-27.2.12-17.2.15-1

All of the following

azurelinux/kernel<6.6.161.1-1

6.6.161.1-1

Microsoft Azure Linux=3.0

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15*

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.15*

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm-5.15*

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15*

ubuntu/linux-lowlatency-hwe-5.15*

ubuntu/linux-nvidia-tegra-5.15*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15*

ubuntu/linux-riscv-5.8*

ubuntu/linux*

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws*

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1069.74~22.04.1

6.8.0-1069.74~22.04.1

ubuntu/linux-azure*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1073.82~22.04.1

6.8.0-1073.82~22.04.1

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1071.78~22.04.1

6.8.0-1071.78~22.04.1

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1073.81~22.04.1

6.8.0-1073.81~22.04.1

ubuntu/linux-gke*

ubuntu/linux-gkeop*

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm*

ubuntu/linux-ibm-6.8<6.8.0-1069.70~22.04.1

6.8.0-1069.70~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency*

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-149.149.1~22.04.1

6.8.0-149.149.1~22.04.1

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8*

ubuntu/linux-nvidia-tegra*

ubuntu/linux-nvidia-tegra-igx*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle*

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1067.71~22.04.1

6.8.0-1067.71~22.04.1

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-149.149~22.04.2

6.8.0-149.149~22.04.2

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-bluefield*

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-realtime*

ubuntu/linux-realtime-6.8<6.8.1-1064.65~22.04.1

6.8.1-1064.65~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<6.8.0-149.149

6.8.0-149.149

ubuntu/linux-aws<6.8.0-1069.74

6.8.0-1069.74

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-aws-7.0<7.0.0-1017.18~24.04.1

7.0.0-1017.18~24.04.1

ubuntu/linux-azure<6.8.0-1073.82

6.8.0-1073.82

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0*

ubuntu/linux-azure-fde<6.8.0-1071.78

6.8.0-1071.78

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0<7.0.0-1019.19~24.04.1

7.0.0-1019.19~24.04.1

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1073.81

6.8.0-1073.81

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0<7.0.0-1017.19~24.04.1

7.0.0-1017.19~24.04.1

ubuntu/linux-gke<6.8.0-1068.77

6.8.0-1068.77

ubuntu/linux-gkeop<6.8.0-1053.57

6.8.0-1053.57

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0*

ubuntu/linux-ibm<6.8.0-1069.70

6.8.0-1069.70

ubuntu/linux-lowlatency<6.8.0-149.149.1

6.8.0-149.149.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1067.70

6.8.0-1067.70

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0*

ubuntu/linux-nvidia-lowlatency<6.8.0-1067.70.1

6.8.0-1067.70.1

ubuntu/linux-nvidia-tegra*

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1067.71

6.8.0-1067.71

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0<7.0.0-1016.18~24.04.1

7.0.0-1016.18~24.04.1

ubuntu/linux-raspi<6.8.0-1068.72

6.8.0-1068.72

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-riscv-7.0<7.0.0-43.43.1~24.04.2

7.0.0-43.43.1~24.04.2

ubuntu/linux-vmware<6.8.0-1010.10

6.8.0-1010.10

ubuntu/linux-xilinx*

ubuntu/linux-bluefield<6.8.0-1036.41

6.8.0-1036.41

ubuntu/linux-raspi-realtime<6.8.0-2056.58

6.8.0-2056.58

ubuntu/linux-realtime<6.8.1-1064.65

6.8.1-1064.65

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1069.74+fips1

6.8.0-1069.74+fips1

ubuntu/linux-azure-fips<6.8.0-1073.82+fips1

6.8.0-1073.82+fips1

ubuntu/linux-fips*

ubuntu/linux-gcp-fips<6.8.0-1073.81+fips1

6.8.0-1073.81+fips1

ubuntu/linux<7.3.0-10.10

7.3.0-10.10

ubuntu/linux-aws<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-azure<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-azure-fde<7.3.0-1004.5

7.3.0-1004.5

ubuntu/linux-gcp<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-oracle<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-raspi<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-realtime<7.3.0-10.10.1

7.3.0-10.10.1

ubuntu/linux-riscv<7.3.0-10.10.1

7.3.0-10.10.1

ubuntu/linux<7.0.0-43.43

7.0.0-43.43

ubuntu/linux-aws<7.0.0-1017.18

7.0.0-1017.18

ubuntu/linux-azure<7.0.0-1020.21

7.0.0-1020.21

ubuntu/linux-azure-fde<7.0.0-1019.19

7.0.0-1019.19

ubuntu/linux-gcp<7.0.0-1017.19

7.0.0-1017.19

ubuntu/linux-gke<7.0.0-1010.11

7.0.0-1010.11

ubuntu/linux-ibm<7.0.0-1018.18

7.0.0-1018.18

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-bos*

ubuntu/linux-oem-7.0<7.0.0-1018.18

7.0.0-1018.18

ubuntu/linux-oracle<7.0.0-1016.18

7.0.0-1016.18

ubuntu/linux-raspi<7.0.0-1023.23

7.0.0-1023.23

ubuntu/linux-realtime<7.0.0-43.43.1

7.0.0-43.43.1

ubuntu/linux-riscv*

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.12.113-1
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 7.2.11-1
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 5.10.273
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 5.15.224
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.1.191
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.6.160
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.12.113
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.18.57
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 7.2.11
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1
Upgrade
Upgrade azurelinux/kernel to a version that resolves this vulnerability.
Fixed in 6.6.161.1-1
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.74~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.82~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.78~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.81~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.70~22.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149.1~22.04.1
Upgrade
Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.71~22.04.1
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149~22.04.2
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1064.65~22.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.74
Upgrade
Upgrade ubuntu/linux-aws-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.18~24.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.82
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.78
Upgrade
Upgrade ubuntu/linux-azure-fde-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1019.19~24.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.81
Upgrade
Upgrade ubuntu/linux-gcp-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.19~24.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1068.77
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1053.57
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.70
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.70
Upgrade
Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.70.1
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.71
Upgrade
Upgrade ubuntu/linux-oracle-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.18~24.04.1
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 6.8.0-1068.72
Upgrade
Upgrade ubuntu/linux-riscv-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-43.43.1~24.04.2
Upgrade
Upgrade ubuntu/linux-vmware to a version that resolves this vulnerability.
Fixed in 6.8.0-1010.10
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 6.8.0-1036.41
Upgrade
Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.
Fixed in 6.8.0-2056.58
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1064.65
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.74+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.82+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.81+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.3.0-10.10
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.5
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 7.3.0-10.10.1
Upgrade
Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.
Fixed in 7.3.0-10.10.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.0.0-43.43
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.18
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 7.0.0-1020.21
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 7.0.0-1019.19
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.19
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 7.0.0-1010.11
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 7.0.0-1018.18
Upgrade
Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1018.18
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.18
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 7.0.0-1023.23
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 7.0.0-43.43.1

Event History

Oct 23, 2026

CVE Published

via MITRE·12:21 PM

Data Sourced

via MITRE·12:21 PM

Description

Data Sourced

via OSV·12:21 PM

DescriptionAffected Software

Data Sourced

via NVD·01:17 PM

Description

Oct 25, 2026

Data Sourced

via Microsoft·08:03 AM

DescriptionSeverityWeaknessAffected Software

Nov 12, 2026

Data Sourced

via OSV·05:56 PM

Severity

Frequently Asked Questions

Which systems are exposed to this issue?

Systems using the Linux kernel bridge multicast code are relevant. The failure condition involves a large number of automatically added STAR_EXCL port groups associated with S,G multicast entries.

What condition causes the stack exhaustion?

During cleanup, deletion of an automatically added STAR_EXCL port group can recurse back into S,G exclude-port cleanup. Each affected port can consume another kernel stack frame, and sufficiently many ports can reach the stack guard page.

CVE-2026-99031: net: bridge: avoid recursive multicast port cleanup

Affected Software

Remediation

Event History

Frequently Asked Questions

Which systems are exposed to this issue?

What condition causes the stack exhaustion?

Company

Resources

Contact